[bunk48]

Hey all

So I just got my M340i xdrive cpo and it came with the 225/45/18 all season runflats :/

Im thinking about going with 225/40/19 in the front which is a +0.4% rolling diameter increase and 255/35/19 in the rear which is 0%.

Would this setup mess up my xdrive since the front and rear diameters are different?

Also any rim and offset suggestions?


Thanks!

[mechman]

Originally Posted by bunk48

Hey all

So I just got my M340i xdrive cpo and it came with the 225/45/18 all season runflats :/

Im thinking about going with 225/40/19 in the front which is a +0.4% rolling diameter increase and 255/35/19 in the rear which is 0%.

Would this setup mess up my xdrive since the front and rear diameters are different?

Also any rim and offset suggestions?


Thanks!

The proposed tire size combo is the standard size from the factory when optioned with the performance tires so you should be fine.

You need a 8.5in wheel in the rear if you choose to go 255 but the front can make do with a 7.5 or 8in wheel for a 225 wide tire.

The stock wheel size on the performance tires from the factory is
19x8 ET27 Front and 19x8.5 ET40 Rear so you want to stay close to those number unless you plan to use spacers.

[bunk48]

Originally Posted by mechman

The proposed tire size combo is the standard size from the factory when optioned with the performance tires so you should be fine.

You need a 8.5in wheel in the rear if you choose to go 255 but the front can make do with a 7.5 or 8in wheel for a 225 wide tire.

The stock wheel size on the performance tires from the factory is
19x8 ET27 Front and 19x8.5 ET40 Rear so you want to stay close to those number unless you plan to use spacers.

Okay perfect!

Will putting 235's on the front reduce understeer?

Thanks for the response!

[Lightngsvt]

Yes, in theory, the wider tire you put on the front in relation to the back should add more grip at the front, reducing understeer.

[G22b58]

Except with a 235 width in the front and a wider tire in the back you will have a hard time to find a good match in rolling circumference. Some say it's important to use the BMW optimized (star marked) tires and in the combinations defined by BMW, because these should have tweaked dimensions to optimize circumference.
I don't know what to believe. I also have 18" wheels (however the staggered combo 225/45-18, 255/40-18) and thinking of replacing Bridgestones with Michelin PS4 (non-RFT). Michelin has star marked PS4 in these dimensions but the answer I get from Michelin is that these are not recommended for xDrive. BMW list of approved tires for my G22 also doesn't list any staggered non-RFT in 18"

[viciousmo]

On a stock suspension XDrive, could I pull off 19x9.5 + 25/19x10.5 + 34? I would run the DINAN spring or H&R, I just don't want to expedite the wear on the struts.

[sayhi2neil]

Hey guys, tire noob here. Same car came with 225/40/r19 on all 4 and thinking of going with 225/45/r18. M340xi 2020. would that work?

[BingoTheClown]

Originally Posted by sayhi2neil

Hey guys, tire noob here. Same car came with 225/40/r19 on all 4 and thinking of going with 225/45/r18. M340xi 2020. would that work?

Well, My 2020 M340i xDrive was purchased used CPO with that exact setup. I have 225/45R18 all around. So . . it does work lol.

[sayhi2neil]

Thank you, it did work for me too. It seems you can go 18 or 19. But for winters they said it's better to use 18.